|Tell your sister . . . I'll be back as a young and vibrant Force ghost!|
There’s a rule that almost every movie and book series adheres to called “Conservation of Characters.” The thrust is simple: a writer/reader spends time introducing, understanding, and relating to a character as they go through conflicts and resolutions. Because of the limited space of books and movies, Conservation of Characters results in a noticeable and significantly lower percentage of death vs. danger.
Television shows have a lot more room to play with this. Actors typically don’t want to sign up just to be killed off, but there is still room over, under, through and around this rule. “Supernatural” plays with this on and off, sometimes “killing” even the main characters, only to have them return after a reasonable story-arc about them being dead.
The point is that it's much easier to change characters over time, through injuries, torture, mental anguish, etc. than it is to realistically kill off that character and have to start the process over. Because of this, often the twist of a movie or a book can be seen some distance off, as the number of characters a writer can introduce has to be reasonable enough for a reader to absorb. The number of characters a writer can reasonably kill off is even less.
It’s not a bad thing. It’s a thing that writers (and readers) should be aware of.
Looking back, I've killed off at least one major character in every genre fiction book I've written. I didn't realize it until I was thinking about this concept. Apparently, I buy into the "writer as bastard" concept and figure that the more fights a character gets into, the more likely they—or someone close to them—are to get killed.